One of the guys who snatched Derwin James' Rolex and gold chain at gunpoint last summer has just been sentenced to NINE YEARS in state prison for the crime ... TMZ Sports has learned.
Back in June 2018 ... officials say a man named Kevin Mitchell rolled up on 23-year-old James and his uncle after they ate at Bossa Nova restaurant on Sunset Blvd.
Officials say Mitchell and another man held the L.A. Chargers superstar defensive back and his uncle at gunpoint ... stealing James' pricey watch and chain.
Cops launched an investigation after the incident .